CacheControlProcessor

public class CacheControlProcessor : CacheControl
    {
        protected override void RunCacheControl(ActionExecutedArgs args)
        {
            Assert.IsNotNull(args, "args != null");

            if (Sitecore.Context.Item != null)
            {
                if (HasRequestMethodGet(args) && DoesntHaveQuerystrings(args))
                {
                    if (ShouldHavePublicCacheControl(args, Sitecore.Context.Item))
                    {
                        SetPublicCacheAndMaxAge(args, Sitecore.Context.Item);
                        return;
                    }
                }

            }
            base.SetNoCacheNoStore(args);
        }
        private bool HasRequestMethodGet(ActionExecutedArgs args)
        {
            return "get".Equals(args.Context.RequestContext.HttpContext.Request.HttpMethod, StringComparison.CurrentCultureIgnoreCase);
        }
        private bool DoesntHaveQuerystrings(ActionExecutedArgs args)
        {
            var nvc = args.Context.RequestContext.HttpContext.Request.QueryString;
            return nvc == null || nvc.Count == 0;
        }
        private bool ShouldHavePublicCacheControl(ActionExecutedArgs args, Item item)
        {
            if (!base.IsDisableBrowserCaching(args))
            {
                if (Constants.ValidTemplateIds.Contains(item.TemplateID) || TemplateIds.Model.Equals(item.TemplateID))
                {
                    if (!HasPersonalization(item))
                    {
                        return true;
                    }
                }
            }
            return false;
        }
        private bool HasPersonalization(Item item)
        {
            if (!HasPersonalizationCacheManager.TryGet(item, out bool result))
            {
                var device = Sitecore.Context.Device;
                foreach (var rendering in item.Visualization.GetRenderings(device, false))
                {
                    if (rendering.Settings.Rules.Count > 0)
                    {
                        result = true;
                        break;
                    }
                }
                HasPersonalizationCacheManager.Set(item, result);
            }
            return result;
        }
        protected void SetPublicCacheAndMaxAge(ActionExecutedArgs args, Item item)
        {
            var timeSpan = TemplateIds.Model.Equals(item.TemplateID) ? 900 : 3600;
            if (!args.Context.RequestContext.HttpContext.Response.HeadersWritten)
            {
                args.Context.RequestContext.HttpContext.Response.SuppressDefaultCacheControlHeader = true;
                args.Context.RequestContext.HttpContext.Response.Headers.Set("Cache-Control", $"public, max-age=0, s-maxage={timeSpan}, stale-while-revalidate={timeSpan / 2}");
                args.Context.RequestContext.HttpContext.Response.Headers.Set("X-Expires", DateTime.UtcNow.AddSeconds(timeSpan).ToString("r"));
            }
        }
    }